More than half of all the single-family homes in the United States were built in the last three decades of the 20th century, and it is estimated that half again of the current total number of dwellings — about 80 million — will need to be built in the next three decades of the 21st century.

Unfortunately, most houses built in the last 50 years were merely plopped down on a piece of land, adhering to zoning laws, and occasionally conservation commissions and planning boards, and forced to face the street like so many soldiers in a row.

The harsh reality is that these sites are often stripped of any existing natural vegetation, provided with roads that are much too wide, and given lot configurations that have little to do with the land they are carved from.

There is seldom any real integration of house and site. It is one of the byproducts of sprawl; we all know it when we see it, and it's a recipe for disaster for the foreseeable future because of its harm to the environment.

Rooftop as Urban Site

When thinking of sustainable site design, most people probably imagine a low-density rural or suburban site somewhere far afield, not a high-density urban one in the heart of a large city.

The new apartments at 1247 Wisconsin Avenue in Washington, D.C., sit on a more unusual site: the rooftop of two existing buildings.
>>>